JP2509630Y2 - Steering wheel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a steering wheel of a vehicle capable of detecting a steering force during steering and reducing an operation delay of a power steering device.

[Prior Art] Conventionally, in a power steering apparatus for a vehicle, a steering force sensor and a steering amount sensor are arranged on a steering shaft to sense the steering force and the steering amount, and the steering force and the steering amount are used to detect the steering force. There was a proposal to correct the cut-off delay.

However, since the steering force sensor and the steering amount sensor detect distortion and displacement of the steering shaft, they are affected by the inertia of the steering wheel itself, and it is difficult to quickly detect an accurate steering force and steering amount. .

Therefore, it has been proposed to dispose a steering force sensor on the steering wheel itself, as described in JP-A-62-105770. The steering wheel described in this publication has an inner ring connected and fixed to a pair of spokes projecting from a boss, a bending beam whose base end is fixed to the boss side, and supported by the spoke so as to be relatively movable in the rotational direction. And a spoke cover to which a tip of the bending beam is fixed, an outer ring connected to the spoke cover and movably supported relative to the inner ring in a rotation direction of a ring portion, and attached to the bending beam. When the steering wheel is steered, the spoke ring moves relative to the spoke as the outer ring moves relative to the inner ring, and the bending beam moves relative to the spoke cover. Is elastically bent in the direction, and the strain gauge bends the bending beam. Detects, adapted to sense the steering force and direction.
With this configuration, the steering force can be detected more accurately than when various sensors are arranged on the steering shaft itself.

[Problems to be Solved by the Invention] In the configuration of the conventional publication, steering force is detected by detecting bending strain of the bending beam, and a strain gauge attached to the bending beam is used for detecting bending strain. It was However, since the amount of distortion of the bending beam differs depending on the position in the longitudinal direction, it is necessary to accurately attach the strain gauge to a predetermined position in order to prevent an error due to the attaching position. However, since the strain gauge is in the form of a thin tape, it is difficult to automate the sticking work, and the sticking work requires manual work and requires skill, which is not suitable for mass production. In addition, since stress is directly applied to the strain gauge itself in response to the strain of the bending beam, durability is deteriorated due to deterioration of the strain gauge due to repeated stress, and the strain gauge easily peels from the bending beam due to moisture,
There is a problem of low reliability.

The present invention has been made in view of the above problems, and its purpose is to detect a steering force without being affected by the inertia of the steering wheel itself, and to have excellent durability, which is suitable for mass production. To provide wheels.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an inner ring connected to a plurality of spokes radially protruding from a boss attached to a steering shaft, and the inner ring. The ring portion is composed of an outer ring arranged so as to be able to move relative to the inner ring in the direction of rotation in a state of covering the periphery of the outer ring, and the relative movement amount of the outer ring with respect to the inner ring is proportional to the steering force. In the steering wheel described above, a bridge circuit including at least a pair of coils, a high frequency oscillation circuit for generating magnetic flux in the coils, and a conversion circuit for converting an inductance change of one coil of the bridge circuit into a voltage change. The main body of the detector is provided on the spoke side, and the magnetic flux generated in the coil is transferred to the outer ring side. A cover for holding the outer ring so as to cover the periphery of the spoke with a gap near the inner ring of the spoke, by providing a magnetic flux density changing member that changes according to the positional relationship with the coil, at a position close to the coil. A member is disposed, and a regulating wall is formed on the cover member or the spoke between the cover member and the upper surface or the lower surface of the spoke along the rotation direction of the ring portion, and the regulating member is provided on the cover member and the spoke. Between the lower surface and each of the lower surface, one of the cover member and the spoke is fixed and abuts on the other, and a vertical position regulating roller is rotatably provided on the radial rotation axis of the ring portion. And the upper and lower surfaces of the spokes, which are not provided with the restriction wall, are in contact with the restriction wall, and the radial position restriction is provided so as to be rotatable by a vertical rotation shaft. It has as its subject matter that was placed over La.

[Operation] In the steering wheel of the present invention, the outer ring rotates relative to the inner ring during steering, and the relative movement amount thereof is proportional to the steering force. When the outer ring moves, the magnetic flux changing member moves together with the outer ring, and along with the movement, the magnetic flux generated in the coil of the detection device body provided on the spoke side changes. As a result, the inductance of the coil changes in accordance with the amount of movement of the outer ring, the change is converted into a voltage change, and the steering force is detected. Since the coil and the magnetic flux changing member are always held in a non-contact state, the stress does not directly act on the detecting portion, and the durability is improved.

Further, even if the outer ring receives a pressing force in the radial direction of the ring portion during steering, the pressing force is mainly received by the radial direction regulation roller arranged between the cover member and the spoke. Further, the gravity of the outer ring itself and the vertical force acting on the outer ring during steering are mainly received by the vertical position regulating rollers arranged between the cover member and the spokes.

When the outer ring receives forces from a plurality of directions and moves relative to the inner ring in the ring rotation direction,
The radial position regulation roller and the upper limit position regulation roller receive the forces from these plural directions and rotate smoothly without sliding together without affecting the other roller, and the outer ring with respect to the inner ring. Move smoothly.

[Embodiment] An embodiment embodying the present invention will be described below with reference to FIGS.

As shown in FIG. 2, the steering wheel 1 has three metal spokes 3 radially protruding from a boss 2 attached to the steering shaft S. At the tips of these spokes 3, an inner ring 5 made of metal and constituting the ring portion 4 is connected and fixed. The boss 2, the spokes 3, and the inner ring 5 may be made of steel and connected by welding, or each part may be integrally cast as an aluminum die cast.

Around the inner ring 5 of the ring portion 4, the inner ring 5 is made of a lightweight metal material such as aluminum.
The outer ring 6 is disposed with a gap H between the outer ring 6 and the outer ring 6. As shown in FIGS. 3 and 5, the outer ring 6 is composed of an upper member 6a and a lower member 6b which are vertically divided into two parts.
A collar portion 6c protruding toward the boss 2 is formed at a position corresponding to each spoke 3. The outer ring 6 is integrated with the periphery of the inner ring 5 by tightening and fixing the flange portions 6c of the upper member 6a and the lower member 6b to the upper cover member 7 and the lower cover member 8 described later with screws 9. It is located in.

The upper and lower cover members 7 and 8 which hold the outer ring 6 screwed to the collar portion 6c are arranged near the ring portion 4 of each spoke 3 so as to cover the periphery of the spoke 3 with a gap. Both cover members 7, 8 are made of a hard synthetic resin such as ABS, PP, etc., and are provided with screw holes 7a, 8a for screwing the collar portion 6c of the outer ring 6, and both cover members 7, 8 are provided on both sides. Collar portions 7b and 8b are provided for tightening and fixing 8 with screw 10 to integrate them.

The upper and lower cover members 7 and 8 are provided with supporting walls 11 and 12 as restricting walls extending along the width direction of the spokes 3 on the surfaces facing the upper and lower surfaces of the spokes 3, respectively. A pair of support shafts 13 and 14 are provided on the support walls 11 and 12, respectively.
Mounted so that it extends along the longitudinal direction of each spindle 1
Rollers 15,1 as vertical position regulation rollers at the tip of 3,14
6 are rotatably supported in contact with the upper and lower surfaces of each spoke 3. Further, a support shaft 17 is erected on the upper surface of the spoke 3 from the support wall 11 to the boss 2 side.
Are rotatably supported in contact with the respective support walls 11.

Further, each upper cover member 7 is formed with a spring seat 7c at a position corresponding to both sides of each spoke 3, and a spring holding member 19 is provided at the center of the upper surface of the spoke 3 corresponding to the spring seat 7c. Is fixed by a screw 20, and a compression coil spring 21 is interposed between the spring seat 7c and the spring holding member 19. As a result, the upper and lower cover members 7 and 8 urge the spokes 3 to be arranged at the central portion of the ring portion 4 in the rotation direction,
The outer ring 6 is held in a predetermined position with respect to the inner ring 5 when no external force acts on the outer ring 6. In this state, both side surfaces of each spoke 3 and the cover member 7,
The gap h with the inner surface of 8 is configured to be about 1 mm.

Rear side of steering wheel 1 (lower side in FIG. 2)
A base end portion of a bending beam 22 having spring elasticity is fixed to the lower surface of the spoke 3 by a bolt 23. The lower cover member 8 is provided with a pair of fitting projections 8c on the boss 2 side of the support wall 13, and the tip of the bending beam 22 is fitted between the fitting projections 8c. . As a result, the steering force is transmitted to the steering shaft S via the bending beam 22 by the turning operation of the outer ring 6, and the relative movement amount of the outer ring 6 with respect to the inner ring 5 is proportional to the steering force. The bending beam 22 is applied to the outer ring 6 when a steering force of 5 kg is applied,
The amount of bending of the tip portion is 1 mm, and the inner surfaces of the upper and lower cover members 7, 8 come into contact with the side surfaces of the spokes 3.

Further, one of the spokes 3 other than the spokes 3 to which the bending beam 22 is attached has a detecting device body 24 for detecting a relative movement amount of the outer ring 6 with respect to the inner ring 5.
Is provided. As shown in FIGS. 3 and 4, the detection device body 24 is attached to the lower surface of the spoke 3 near the tip end with a screw 25,
It is electrically connected via a connector 26 to a hydraulic controller that controls a variable throttle arranged in a hydraulic circuit of a power steering (not shown).

As shown in the circuit diagram of FIG. 1, the detection device body 24 includes a bridge circuit 27 including a pair of coils L1 and L2, and the coil L1 and L1.
A high frequency transmission circuit 28 for generating a magnetic flux in L2, and an amplitude detection unit 29 as a conversion circuit for converting an inductance change of one coil L2 of the bridge circuit 27 into a voltage change.
And an amplification section 30 for amplifying the output of the amplitude detection section 29. The coils L1 and L2, which are constituent elements of the bridge circuit 27, have one end connected to the high-frequency transmission circuit 28, the other end connected to a parallel circuit of the capacitor C and the resistor R, and one end of the parallel circuit grounded. . And the bridge circuit
One coil L2 constituting 27 is arranged so as to be located in the vicinity of the central portion of the lower cover member 8 in a state orthogonal to the longitudinal direction of the spoke 3. On the other hand, a convex portion 31 is formed on the boss 2 side of the support wall 12 of the lower cover member 8, and a magnet 32 as a magnetic flux changing member is fixed to the tip of the convex portion 31 in a state of being close to the coil L2. There is.

As shown in FIGS. 2, 3, and 5, the cover 33 covers the upper and lower surfaces of the spokes 3 and the upper portion of the boss 2. Further, in order to improve the appearance of the steering wheel 1, it is desirable to wrap a leather or the like (not shown) around the outer ring 6.

Next, the steering wheel 1 configured as described above
The operation of will be described.

Now, when the steering force for gripping the ring portion 4 and rotating it in one of the left and right directions is applied to the ring portion 4, the steering force first acts on the outer ring 6, and the outer ring 6 acts on the elastic force of the bending beam 22. The bending beam 22 is deflected against it, and the bending beam 22 is relatively moved in a predetermined direction with respect to the inner ring 5 by an amount corresponding to the steering force. After the outer ring 6 is moved by a predetermined amount with respect to the inner ring 5, the inner ring 5
Is rotated integrally with the outer ring 6 to rotate the steering shaft S in a predetermined direction. As described above, there is a gap h of 1 mm between each upper and lower cover member 7, 8 and both side surfaces of the spoke 3, and until each upper and lower cover member 7, 8 comes into contact with either side surface of the spoke 3. , The steering force applied to the outer ring 6 is transmitted to the spoke 3 via the bending beam 22, and after the upper and lower cover members 7 and 8 come into contact with one of the side surfaces of the spoke 3, the steering force is applied to the bending beam 22. And transmitted to the spokes 3 through the upper and lower cover members 7 and 8.

The steering force applied to the steering wheel 1 varies depending on the traveling speed of the vehicle and the like, and is generally the largest at about 5 kg during stationary steering. In addition, it is smaller in high-speed running than in low-speed running, and is 2-3 kg at maximum in normal running. Therefore, when the steering wheel is operated during traveling, the steering force is less than 5 kg, the bending amount of the tip of the bending beam 22 is less than 1 mm, and even if the outer ring 6 is moved by the steering force, the upper and lower cover members 7, 8 are Does not contact the side surface of the spoke 3. That is, the amount of displacement of the outer ring 6 from the origin when the outer ring 6 moves corresponds to the magnitude of the steering force.

When the outer ring 6 is moved relative to the inner ring 5, the magnet 32 attached to the support wall 12 of the lower cover member 8 moves relative to the coil L2, and the positional relationship between the magnet 32 and the coil L2 changes. To do. Bridge circuit of the detector body 24
The high frequency is applied to the 27 from the high frequency transmission circuit 28,
A magnetic flux is generated in both coils L1, L2 by applying a high frequency to both coils L1, L2. On the other hand, the magnetic flux generated in the coil L2 is reduced by the action of the magnet 32, and the inductance thereof is reduced. The value of the inductance of the coil L2 changes depending on the positional relationship of the magnet with respect to the coil L2.

Measurement result of the coil inductance change by the model when the coil is moved in parallel with the axis of the magnet coil so that the gap between the surface of the magnet and the outer circumference of the coil is 0.5 mm with a high frequency of 10 kHz applied to the coil. Is shown in FIG.
(In the measurement, the magnet was moved with the origin 8 mm away from the position corresponding to the center of the coil.) As shown in the figure, the inductance of the coil is the smallest at the position where the magnet corresponds to the center of the coil. And becomes larger as it moves away from the same position. Then, in the portion where the amount of change in inductance is large, the amount of change in inductance becomes greater than 0.4 mH due to the movement of the magnet of 1 mm, which is equal to the amount of movement of the outer ring 6 until the upper and lower cover members 7 and 8 contact the spokes 3. . When a high frequency wave having a constant frequency and amplitude is applied to the coil, the high frequency wave after passing through the coil changes in amplitude with the change in the inductance of the coil. Then, by amplifying, even a small movement amount of the magnet can be accurately detected.

In this embodiment, the high frequency wave that has passed through one coil L2 of the bridge circuit 27 is the inner ring 5 of the outer ring 6.
It changes with the relative movement of the magnet 32 with respect to the coil L2 due to the relative movement with respect to. Further, the high frequency after passing through the other coil L1 has a constant amplitude regardless of the movement of the outer ring 6. Therefore, a constant voltage V1 is input to the non-inverting input terminal of the operational amplifier 34 of the amplification unit 30, and a voltage V2 corresponding to the relative movement amount of the magnet 32 with respect to the coil L2 is input to the inverting input terminal, and the differential amplification circuit Difference between both voltages (V1-V2)
Is amplified and output from the output terminal. The relationship between the movement amount (displacement amount) of the magnet 32 and the output voltage is as shown in FIG. As shown in the figure, when the steering force is not applied to the outer ring 6, the output voltage from the amplification unit 30 is maintained at 2.0V, and the outer ring 6 moves to the right relative to the inner ring 5. When rotated, the output voltage becomes greater than 2.0V,
When rotated to the left, the output voltage becomes less than 2.0V.
Then, this output is input to the hydraulic controller of the power steering, the power steering device is started, and the power steering is operated with an optimum force corresponding to the steering force. That is, when a steering force is applied to the ring portion 4 of the steering wheel 1 to rotate the outer ring 6,
Immediately, the steering force and the turning direction are detected, and the delay in power steering can be reduced.

When the vehicle is left outdoors, the temperature of the steering wheel rises to around 60 ° C in the hot summer and drops to around 20 ° C below freezing in winter in the cold region, so the ambient temperature around the coil changes greatly. On the other hand, the inductance of the coil generally has temperature dependence. Therefore, when the coil inductance has a large temperature dependency, the error becomes large when the displacement amount of the magnet 32 is detected by simply converting the coil inductance change into a voltage change. FIG. 8 shows the results of measuring the temperature dependence of the inductance of the above coil at a frequency of 10 kHz. As is clear from the figure, the coil inductance increases substantially in proportion to the ambient temperature, and the rate of change is about 0.08 mH per 20 ° C. This value corresponds to the displacement of the magnet 32 of 0.2 mm and cannot be ignored. However, since the pair of coils L1 and L2 are used as the constituent elements of the bridge circuit 27 in the detection device of this invention, even if the inductance of both coils L1 and L2 fluctuates due to temperature change, Since amplification is performed by the amplification unit 30 based on the difference in inductance, the temperature dependence of the coil has almost no effect on the detection result of the displacement amount.

Further, in this embodiment, the outer ring 6 is supported by upper and lower cover members 7 and 8 arranged so as to cover the respective spokes 3, and the respective cover members 7 and 8 correspond to the respective spokes 3 and the respective upper and lower cover members 7 and 8. Rollers 15 and 16 provided on the support walls 11 and 12 of the spoke 3 and abutting on the upper and lower surfaces of the spoke 3, and a regulating roller 18 provided on each spoke 3 and abutting on the boss 2 side surface of the support wall 11 of the upper cover member 7. Since it is supported by, the forces acting on the outer ring 6 are divided and carried by the rollers 15, 16 and 18, and the outer ring 6 is smoothly moved with respect to the inner ring portion 5 to detect the steering force. Definitely done.

It should be noted that the present invention is not limited to the above embodiment, and for example, instead of moving the magnet 32 in parallel with the axis of the coil L2, the magnet 32 is moved along the extension of the axis of the coil L2. Alternatively, in the vicinity of the other coil L1 forming the bridge circuit 27, the magnet is arranged in the same state as the positional relationship between the magnet 32 and the coil L2 when the steering force is not applied to the outer ring 6, Metal may be used as the magnetic flux changing member instead of the magnet. Further, in the above embodiment, the compression coil spring 21 is provided as a means for returning the outer ring 6 to the original position when the steering force is no longer applied, but the elastic force of the bending beam 22 is used for the return. May be. Furthermore, the number of spokes 3 may be set to a number other than three,
A supporting structure for the inner ring 5 and the outer ring 6 is disclosed in JP-A-62-105.
The one disclosed in Japanese Patent No. 770 may be adopted.

[Advantages of the Invention] As described above in detail, according to the present invention, the steering force is detected by detecting the relative movement amount of the outer ring with respect to the inner ring, and the coil and the magnetic flux changing member serving as the detecting portion are detected. Since it is held in a non-contact state, it does not deteriorate due to operation, and unlike conventional devices that use a strain gauge to detect steering force, stress does not directly act on the detection part, improving durability and reliability. . Further, although the inductance of the coil has temperature dependency, since the bridge circuit including a pair of coils is used, the influence of the temperature dependency of the coil can be ignored. Furthermore, since the electronic components of each circuit constituting the detection device can be mounted by the conventional mounting device, they are suitable for mass production.

Further, in the steering wheel of the present invention, even if a force in various directions is applied to the outer ring, the movement resistance of the outer ring with respect to the inner ring can be reduced, and the delay in detecting the steering force can be reduced.

Further, since the outer ring is supported by the spokes via the cover member, a large gap can be secured between the inner ring and the outer ring. That is, when the conventional outer ring is supported by the inner ring portion, it is necessary to manufacture both the inner ring and the outer ring into an annular shape with good dimensional accuracy over the entire circumference. It was very time-consuming to manufacture. In this invention, since the gap between the inner ring and the outer ring can be made large, it is possible to easily manufacture the inner ring and the outer ring without sufficiently controlling the accuracy of the inner ring and the outer ring. .

[Brief description of drawings]

1 to 9 show an embodiment embodying the present invention. FIG. 1 is a circuit diagram of a displacement detecting device, FIG. 2 is a plan view of a steering wheel, and FIG. 3 is FIG. III-III
A line enlarged sectional view, FIG. 4 is a partially cutaway arrow A view of FIG. 3, FIG. 5 is an enlarged sectional view taken along line VV of FIG. 2, and FIG. 6 is VI- of FIG.
VI line sectional view, FIG. 7 is a graph showing the relationship between the displacement of the magnet and the change of the inductance of the coil, FIG. 8 is a graph showing the temperature dependence of the inductance of the coil, and FIG. 9 is the displacement of the outer ring. It is a graph which shows the relationship between quantity and the output voltage of a detection apparatus. 2 ... Boss, 3 ... Spoke, 4 ... Ring part, 5 ...
Inner ring, 6 ... Outer ring, 22 ... Bending beam, 24 ... Detection device body, 27 ... Bridge circuit, 28 ...
… High frequency oscillator circuit, 29 …… Amplitude detector as conversion circuit, 32 …… Magnets as magnetic flux changing member, L1, L2 …… Coil, S …… Steering shaft.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Tatsuya Terayama, Tatsuya Terayama, Nagachi 1 Ochiai, Kasuga-mura, Nishikasugai-gun, Aichi Toyoda Gosei Co., Ltd. Toyoda Gosei Co., Ltd. (72) Inventor Mt. Fujiyama 3-1-1 Hinodai, Hino-shi, Tokyo Hino Motors Ltd. (72) Inventor Koji Harada 3-1-1 Hinodai, Hino-shi, Tokyo (56) Reference JP 62-105771 (JP, A) JP 1-244322 (JP, A)

Claims (1)

(57) [Scope of utility model registration request] 1. An inner ring (5) connected to a plurality of spokes (3) radially protruding from a boss (2) attached to a steering shaft (S), and a periphery of the inner ring (5). The outer ring (6) is arranged so as to be movable relative to the inner ring (5) in the direction of rotation so as to cover the inner ring (5), and the ring portion (4) is formed, and the inner ring (5) of the outer ring (6) is formed. In a steering wheel configured such that the amount of relative movement with respect to the steering force is proportional to the bridge circuit (27) including at least a pair of coils (L1, L2), and for generating magnetic flux in the coils (L1, L2). High frequency oscillator circuit (28) and the bridge circuit (27)
A detection device body (2) provided with a conversion circuit (29) for converting an inductance change of one coil (L2) into a voltage change.
4) is provided on the spoke (3) side, and on the outer ring (6) side, the magnetic flux density changing member (32) that changes the magnetic flux generated in the coil (L2) according to the positional relationship with the coil (L2). ) Is provided close to the coil (L2), and an outer ring (6) is held near the inner ring (5) of the spoke (3) so as to cover the periphery of the spoke (3) with a gap. A cover member (7, 8) is disposed, and the cover member (7, 8) or the spoke (3) is provided with the cover member (7, 8) between the cover member (7, 8) and an upper surface or a lower surface of the spoke (3). A restriction wall (11) is formed along the rotation direction of the ring portion, and the cover member (7, 8) is provided between the cover member (7, 8) and the upper and lower surfaces of the spoke (3). The spokes (3) are fixed to one side and abut against the other side, and the ring part rotates in the radial direction. Vertical position restriction roller at (15,1
6) is rotatably provided, and the cover member (7, 8) and the upper and lower surfaces of the spokes (3) are not provided with the restriction wall (11), while the restriction wall (11) is provided. A steering wheel having a radial position regulating roller (18) arranged in contact with and rotatable about a vertical rotation shaft.